Further to commit dcd8df258 (shell: improve bash compatibility of
read built-in):

- Check explicitly for a timeout rather than implicitly via non-
  zero errno.

- If poll() fails attempt to process any data collected so far,
  as is done in all other cases of failure.

function                                             old     new   delta
shell_builtin_read                                  1360    1340     -20
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-20)             Total: -20 bytes

Signed-off-by: Ron Yorston <[email protected]>
---
 shell/shell_common.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/shell/shell_common.c b/shell/shell_common.c
index 754fef34b..552c1ece0 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -191,7 +191,7 @@ shell_builtin_read(struct builtin_read_params *params)
        delim = params->opt_d ? params->opt_d[0] : '\n';
        do {
                char c;
-               int timeout;
+               int timeout, ret;
 
                if ((bufpos & 0xff) == 0)
                        buffer = xrealloc(buffer, bufpos + 0x101);
@@ -217,15 +217,15 @@ shell_builtin_read(struct builtin_read_params *params)
                pfd->events = POLLIN;
 
                /* test bb_got_signal, then poll(), atomically wrt signals */
-               if (check_got_signal_and_poll(pfd, timeout) <= 0) {
+               if ((ret = check_got_signal_and_poll(pfd, timeout)) <= 0) {
                        /* timed out, or some error */
-                       err = errno;
-                       if (!err) { /* timed out */
+                       if (ret == 0) { /* timed out */
                                retval = (const char *)(uintptr_t)2;
                                break;
                        }
+                       err = errno;
                        retval = (const char *)(uintptr_t)1;
-                       goto ret;
+                       break;
                }
                if (read(fd, &buffer[bufpos], 1) != 1) {
                        err = errno;
@@ -332,7 +332,6 @@ shell_builtin_read(struct builtin_read_params *params)
                params->setvar("REPLY", buffer);
        }
 
- ret:
        free(buffer);
        if (read_flags & BUILTIN_READ_SILENT)
                tcsetattr(fd, TCSANOW, &old_tty);
-- 
2.50.1

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